Sound absorptive and fireproof body



April 7, 1936- G. H. ELLIS 2,036,467

SOUND ABSORPTIVE AND FIREPROOF BODY Filed July 31, 1931 2 Sheefcs-Shefl' 1 INVENT'OR GEoReE H- ELLIS Arromvsys April 7, 1936. G. H. ELLlS SOUND ABSORRTIVE AND FIREPROOF BODY Filed July 31, 1931 2 Sheets-Sheet 2 Iwvgwron 650F265 H.EL-I-I5 Ill Patented Apr. 7, 1936 UNITED STATES PATENT OFFICE George H. Ellis, St. Paul, Minn, assignor to The Insulite Company, Minneapolis, Minn, a. corporation of Minnesota Application July 31, 1931, Serial No. 554,289

H Claims.

This invention relates to production of bodies which are both highly fire-proof and soundabsorptive.

Objects of the invention are to cheaply produce bodies eachv of which has the above mentioned qualities; to provide a method or process for producing such bodies; to provide a method of using such bodies to form or face a wall; and to-provide ornamental bodies.

Features of the invention include the products, and the process for making the products; the method of building a wall with the products; and the production of a product which has working surfaces which are ornamental.

Objects, features and advantages of the invention will be set forth in the description of the drawings forming a part of this application, and in said drawings Figure l is a perspective view of the laminated body, from which the final product of this in vention is obtained by cutting on lines BC;

Figure 2 is a face view of the finished product;

Figure 3 is an edge view of Figure 2;

Figure 4 is a face view illustrating the method of placing a plurality of products of this invention when forming a wall;

Figure 5 is a horizontal section showing the product applied as a facing for a plastered wall see line 55 of Figure 4;

Figure 6 is a view similar to Figure 5, showing the application of a modified form of the prod uct wherein each. product bridges and directly engages the studding, to take the place of lath and plaster;

Figure 7 is an edge view of the modified product of Figure 6; and

Figure 3 is a detailed enlargement of the structure of Figure 4 illustrating how the terminal fire-proof layer of one slab protectingly cooperates withthe exposed edge faces of another slab.

The first steps in the process are the fabricatlon of suitable fibrous air-filled, sound-absorptive sheets. In this embodiment of the invention,

the sheets are formed from combustible material by a paper-making process.

Referring to Figure 1, which represents a loglike body formed from alternate layers of sheets of fibrous material, and thin sheets of fire-proof material. This figure shows the body produced bythe first series of steps of the process, and includes all the steps, but the last step of cutting along lines BC to form the final product shown in Figures 2 and 3.

The first steps consist in fiberizlng any suitable material, for example wood, preferably raw (Cl. 154-4t) wood, including various soft woods and saw mill waste or forest waste. The fiberization may be carried out by the grindstone process. Fiberization is controlled, to provide long sliver-like fibers, as long as possible and too long and too coarse for use in the manufacture of the coarsest grade of paper. Pulp is very cheaply produced by this method. The pulp is then well hydrolized and is run from the pulper into any suitable machine, such as a cylinder felting machine, to form a relatively thick sheet, or slab.

The sheet is then delivered to and run through a roller press, the function of which is to remove a major portion of the water. prior to passage through a drier. Drying is accomplished by heating without pressure to produce a soft porous, airiilled sheet, which may have a specific gravity ranging from .2 to about .3.

The soft porous sheet is generally dried after forming, and before the cement is applied. The asbestos paper is generally dry when received. The sheets are cut into suitable lengths, the separate sheets being indicated by the numeral l. Each sheet is run through a gluing machine, which applies the fire-resisting cement to each of the opposite faces of the sheet. A cementlike substance which has been found proper for this purpose is a mixture of three parts of silicate of soda and one part of whiting. This cement acts as an air-excluding layer or film. The cemachine, and glue applied to both upper and lower faces, and then to the top of each of these sheets is applied a sheet of fire-proof material. The sheets thus formed are then superposed to form the laminated body of Figure 1. Each sheet is about one-half an inch thick, and about ten feet long by four feet wide, and the height of the pile is about four feet. The sheets extend in direction indicated by the arrows A which correspond to their direction of motion during fabrication.

The sheets are produced by a papermaking process, and the ends of substantially all of the individual fibers (diagrammatically indicated) face in direction of motion, as during fabrication of the sheet. The fibers are indicated at 8.

The assembling may be manual or an automatic operation but in any event, the asbestos faced sheets are stacked while the cement is wet, to form a laminated log-.like or timber-like body.

The amount of pressure applied after the laminated log-like body is formed is merely sufficient to cause proper contact throughout the cementing areas. The log-like body thus formed requires about ninety-six hours to properly dry in the air; about two hours to dry in a drier in which the temperature is maintained at 250 degrees Fahrenheit. The asbestos paper found most advantageous weighs about six and onehalf pounds to the one hundred square feet.

After the body is formed, as shown in Figure 1, a series of cuts are made along the lines 18-0 to produce bodies each having the structural characteristics shown in Figures 2 and 3. This body is the final product of this invention. This body may be of various thicknesses but is generally slab-like.

As before stated, the sheets I are formed by a paper-making process to provide porous air-filled relatively thick bodies, and these bodies, as superposed to form the laminated body, all extend in a direction corresponding to their direction of motion during fabrication. In this way the long axes of substantially all of the fibers lie in planes which are parallel with top and bottom of the sheet during fabrication. Moreover, by the paper-making process, the long axes of substantial- 13, all fibers assume a position which is substantially parallel with the direction of motion. In any event, the fibers are floated into paper-. making position, and in the laminated product (as before cutting on lines BC) the layers assume the relative position mentioned.

Those faces of greatest area of the product (either of which is adapted to be exposed to view, or be placed against the plaster or studding) correspond to the front and rear edges of the sheets, as during fabrication, are referred to as the working faces, and are respectively indicated at I0I I. Those edges of the product which correspond to the sides of the sheet, as during fabrication, are respectively indicated at I2I3.

The intimate structure of the product of Figures 2 and 3 may be likened to a series of very small tubes opening at the surfaces Ill-II and thus so disposed that the sound waves impinging these surfaces, enter the tubes in a direction substantially colinear with their long axes. The cutting of the laminated structure of Figure 1 perpendicularly to a direction corresponding to direction of motion of the sheets I during fabrication (and, therefore, transversely of the long axis of the individual fibers) gives the material very great fire-resisting, and sound-absorption qualities. The cutting of this laminated structure is somewhat similar to the cross cutting of a log. The first resistant action is partly due to the fact that the fire is applied against the ends of the fibers, and is somewhat analogous to the application of fire to the end of a log, in an attempt to burn it.

One of the products of this invention consists essentially of alternate layers or sheets of fibrous material, and layers of non-combustible material, cemented together by a non-combustible substance. The working faces of the product are defined by the coplanar end surfaces of the sheets, so that sound-absorption is increased and combustibility decreased. It has been found that the product owes some of its flre-proofness to the fact that the cementing layer of the non-combustible material prevents the infiltration of the amount of air necessary to support combustion.

The sound-absorption quality is believed to be due principally to the fact that the sound waves impinge the ends of the fine fibers, and spaces between them, and that the arrangement of the fibers virtually provides long tubes in which the cross-sectional area is, for example, in the neighborhood of twenty-nine times less than the length of the tube.

The following comparative fire tests were made between the combustible material of sheets I, and the product of Figures 2 and 3. After application of flame to sheet I, for six minutes at 1700 degrees Fahrenheit, the sheet was burned through. There was flame. With the product of this invention, the same test was applied for forty minutes; charring took place but no flame whatever was produced during the test, and on ,iemoval'of heat there was no smouldering. The

area of application of flame in both cases was about one foot in diameter. Other tests were made to decide the relative acoustic values of the combustible material of sheet I, and of the new product. The standard of comparison is an open window, the tested material having the samearea as the open window. The acoustic absorption of the material of sheet I was about thirtyseven per cent. The acoustic absoption of the material of this invention was about forty-four per cent (sixty-eight per cent only is theoretically possible).

Another feature of the invention relates to the arrangement or use of the product represented in Figure 3, in forming a wall or a wall facing. Referring to Figure 5,'numeral II indicates studding, the numeral l5 lath, and the numeral It a. layer of plaster. In this figure, as well as in Figure 4, the laminated slab-like product of this invention has the form of a square, and these squares are arranged as shown in Figure 4, with one face engaging the plaster. noted that the layers I-4 of one section are perpendicularly arranged to the layers of a contiguone section. By this arrangement, an ornamental effect is also produced which is a feature of the invention. Those faces of the bodies which are exposed in the room are beveled for ornamental purposes. I

In Figure 7, a form of product has been shown which is faced with an asbestos sheet II or with a sheet of suitable fire-proof material, secured by suitable fire-proof cement (not shown). Figure 6 shows the application of this form of the inven tion, which form is particularly advantageous where no lath and plaster are used. In this case, the slabs themselves form substantially the entire wall. In Figure 6, the numeral In indicates the studding. It will be noticed that the asbestos facing I1 is on that side which engages the studding so that a fire-proof surface is obtained at each face of greatest area of the slab.

In all so-called fire-proof material known to me, there is substantially no sound-absorbing ability or if there is any, it is very low. Moreover, in all these materials known to me, objectionable .gasesare generated during a burning period. On the other hand, none of the soundabsorbing bodies known to me have any practicable degree of fire-resisting ability. The qualities of the product of this invention partly result from the method or process by which it is made, and partly result from the character of the material used in the making. Therefore. the prod- It will be not can be advantageously and accurately defined, partly by the process of making it.

It has been found by experiment that when the laminated slab of this invention is one inch thick, and when the layers l of the combustible material are one-half an inch thick, and after the board is submitted to heat of 1700 degrees Fahrenheit for 40 minutes, there is a 55.5 per cent loss in weight. A slab of the same dimensions has a sound-absorbing ability of 43 per cent.

When a slab one inch thick and composed of laminations of the combustible material which are of an inch thick, is submitted to the above test, there is a loss of weight of 65.1 per cent. The sound-absorbing ability of this slab is 45 per cent.

When a slab one inch thick, in which the laminations of the combustible material are A; of an inch thick, is submitted to the above test, the loss of weight is 75 per cent. The sound-absorbing ability is 47.7 per cent.

These experiments indicate that the fire resisting ability is inversely as the sound absorbing ability. It is to be noted that in these tests, the asbestos paper is always the same thickness. In other words, only the thickness of the laminations composing the slab is changed.

It is contemplated herein to vary the thickness of the elements I and to vary the density of the material from which these elements are made. By reducing the thickness of the elements l or by raising their density, the sound-absorbing ability is decreased and fire-resisting property in creased. By increasing the thickness and/or decreasing the density, the sound-absorptive quality is increased and the fire-resistance property decreased.

When the elements I are of very low density, for example ten pounds to the cubic foot, the sound-absorbing quality is increased, the thick ness being the same. It is contemplated herein to vary the thicknesses and densities within certain ranges.

I claim as my invention: 1. A laminated sheet-like structure consistin of alternate sheets of combustible material and sheets of non-combustible material cemented together, the working faces of said structure being defined by the coplanar end surfaces of the sheets.

2. A laminated sheet-like structure consisting of alternate sheets of combustible material and sheets of non-combustible material cemented together by a non-combustible substance, the working faces of said structure being defined by the coplanar end surfaces of the sheets.

3. A laminated sheet-like structure consisting of alternate sheets of fibrous material and sheets of non-combustible material cemented together by a non-combustible substance, the working faces of said structure being defined by the coplanar end surfaces of the sheets.

4. A laminated sheet-like structure consisting of alternate thick sheets of combustible material and thin sheets of non-combustible material cemented together by a non-combustible substance, the working faces of said structure being defined by the coplanar end surfaces of the sheets.

5. A sheet-like body consisting of alternate layers of thick sheets of fibrous material and thin sheets of fire-proof material in which the end surfaces of all sheets are substantially coplanar at each of two opposite face sides, and in which the greater number of individual fibers of the fibrous material have their long axes substantially perpendicular to those face sides.

6. A sheet-like body consisting of alternate layers of sheets of fibrous material and thin sheets of fire-proof material, in which the end surfaces of all sheets are substantially coplanar at each of two opposite face sides.

7. A laminated body consisting, of alternate layers, of sheets of fibrous material fabricated by a paper-making process, and sheets of fire-proof material cemented together, in which the ends of substantially all of the individual fibers of the fibrous material face in direction of the working faces of the body.

8. A laminated body consisting of alternate layers, of sheets of fibrous combustible material fabri'cated by a paper-making process, and sheets of fire-proof material cemented together in which the ends of substantially all of the individual fibers of the fibrous material face in direction of the working faces of the body.

9. A sheet-like body consisting, of alternate layers, of thick sheets of fibrous material fabricated by a paper-making process, and thin sheets of fire-proof material cemented together, in which the ends of substantially all of the individual fibers of the fibrous material face in direction of the working faces of the body.

10. A sheet-like body consisting of alternate layers of sheets of fibrous material, and thin sheets of fire-proof material in which the ends of substantially all of the individual fibers of the fibrous material face in direction of the working faces of the body.

11. A laminated board consisting of thick sheets of fibrous material and thin sheets of noncombustible material alternately interposed between said thick sheets, the working faces of greatest area of the board being defined by the coplanar end surfaces of the thick sheets.

12. A sheet-like body consisting of layers of thick sheets of porous fibrous material, the faces of greatest area of the sheet being defined by the coplanar end surfaces of the sheets, and a sheet of non-combustible material cemented to one sheet-end-defined face of the body by fireproof cement.

13. A sheet-like body consisting of layers of thick sheets of porous fibrous material, the faces of greatest area of the sheet being defined by the coplanar end surfaces of the sheets, and in which layer sheets have the long axes of the greater number of their individual fibers extending in a direction substantially perpendicular to those faces of greatest area which are defined by the coplanar end surfaces of the larger sheets, and thin sheets of non-combustible material alternately interposed between-said thick sheets.

14. A board-like body consisting of layers of fibrous combustible and non-combustible material, said combustible material being fabricated by a paper making process, the faces of greatest area of the body being defined by the coplanar end surfaces of the sheets, and in which the great majority of the ends of the individual fibers of the fibrous material point in a direction of said faces of greatest area which are defined by the coplanar end surfaces of the layers.

GEORGE H. ELLIS. 

